1. Field of the Invention
This invention relates generally to an overrunning, one-way drive device, such as a brake or clutch, whose engaged and disengaged states are selectively controllable.
2. Description of the Prior Art
Conventionally a one-way brake (OWB) or one-way clutch requires two circular rings or raceways, because the raceway that transmits input torque contains the locking elements, such as rollers, struts, or rockers. The input race contains the struts because centrifugal forces are used to move the locking elements away from the output race, which reacts torque. The output raceway is annular, because the locking elements may stop at any location against the output raceway.
Centrifugal force is used to move the locking elements away from the output raceway to limit the duty cycle on the locking elements and springs during the overrun phase of the OWB. If centrifugal force were not employed in this way, the locking elements would wear prematurely and the spring duty cycle could cause premature failure.
The raceways should be annular to satisfy the need to distribute the mass of the rotating components evenly, thereby avoiding an objectionable amount of unbalance.
But conventional raceways for one-way clutches and brakes are expensive, heavy and require too much space.